1. Field of the Invention
Example embodiments of the present invention relate to thin film structures, capacitors and methods of forming the same.
2. Description of the Related Art
A material having a higher dielectric constant may be used for a gate insulation layer of, for example, a metal oxide semiconductor (MOS) transistor or a dielectric layer of a capacitor. A higher dielectric constant may have a thin equivalent oxide thickness (ETO) and may more efficiently reduce a leakage current generated between a gate electrode and a channel region or between a lower electrode and an upper electrode. Zirconium oxide (ZrO2), for example, may be used as the material having the higher dielectric constant. For example, a method of forming a film including zirconium oxide may use tetrakis-methyl ethyl amino zirconium (TEMAZ; Zr[N(CH3)(C2H5)]4) and a method of forming a zirconium oxide film for a dielectric layer of a capacitor may use zirconium chloride (ZrCl4).
A multi-layered structure, which may include a zirconium oxide, may be used for a dielectric layer of a capacitor. A dielectric layer of a capacitor may include an aluminum oxide film and an oxide film or a composite film formed on the aluminum oxide film. The oxide film may include tantalum oxide, zirconium oxide or hafnium oxide, and the composite film may include hafnium-aluminum oxide or lanthanum-aluminum oxide.
In an alternative, a dielectric layer of a capacitor may include a silicate interface film and a higher dielectric film formed on the silicate interface film. The higher dielectric film may include a hafnium oxide film, a zirconium oxide film, a tantalum oxide film, an aluminum oxide film, a titanium oxide film, an yttrium oxide film, a barium-strontium-titanium oxide (BST) film, a plumbum-zirconate-titanate (PZT) film. In another alternative, a dielectric layer of a capacitor may include a silicon oxide film, a silicon nitride film, an aluminum oxide film, a tantalum oxide film, a titanium oxide film, a hafnium oxide film, a zirconium oxide film, a BST film or a PZT film.
The energy band gaps and dielectric constants of oxides such as Ta2O5, Y2O3, HfO2, ZrO2, Nb2O5, BaTiO3 and SrTiO3, which may be used as dielectric materials, are graphically illustrated in FIG. 1.